A CDN is a new network architecture added to an existing internet protocol (IP) transmission network, where the network architecture mainly includes parts such as distributed storage, load balancing, network request redirection, and content management, while content management and global network traffic management are a core of the CDN. Specifically, the CDN publishes content of a website to a network “edge” proximate to a user, so that the user can obtain required content proximately by determining proximity and a server load. This solves the network congestion and low response speed problems that are caused by low network bandwidth, heavy user access traffic, and uneven node distribution when a user accesses the network.
Specifically, in the CDN, a service request of a user terminal may be routed by using a redirection routing manner (for example, Hyper Text Transfer Protocol (HTTP) redirection); the service request initiated by the user terminal is resolved by a domain name system (DNS) and routed to a CDN routing device; the CDN routing device may select, according to a geographic location of the terminal and content requested by the terminal, a proper cache node to provide content for the user terminal; the CDN routing device modifies a domain name in the received service request, constructs a new domain name, and redirects the user terminal to the selected cache node in the CDN by carrying the new constructed domain name in a returned redirection response message; because the new constructed domain name is carried when the user terminal sends the service request to the cache node, a limitation is caused to an application scenario where cookie information needs to be used to authenticate a terminal user or record user history access information.